Latch guard



y 1963 VA. J. GRAVELLE 3,097,003

LATCH GUARD Filed Aug. 14, 1961 INVENTOR.

United States Patent 3,097,008 LATCH GUARD Arthur .I. Gravelle, Canadian Research and Development Foundation, 1434 Queen St. W., Toronto 3, 0ntario, Canada Filed Aug. 14, 1961, Ser. No. 131,208 3 Claims. (Cl. 292-346) This invention relates to improvements in door latches and more particularly to improvements in safety devices for door latches of the spring loaded, sliding bolt type.

It is necessary to mount door locks of the spring loaded, sliding bolt variety with a gap existing between the lock and the striker to permit free relative arcuate movement therebetween, having the disadvantage that a thin, pliable strip of material may be inserted into the gap so formed in such a manner as to manipulate the spring loaded latch back into the lock, thus permitting the door to be opened. Thus, the gap between the door lock and its striker frequently permits illegal entry into premises which the locks were originally installed to protect.

It is an object of this invention to provide a latch guard which will block the gap between the door lock and the striker plate and thus prevent the manipulation of the latch slide bolt without the use of a key.

It is another object of this invention to provide a latch guard which may be inexpensively produced.

It is another object of this invention to provide a latch guard with a self-adjusting adapter that will conform to any varying width of gap for universal attachment to protect substantially all doors which may be fitted with spring loaded slide latches.

It is a further object of this invention to provide a latch guard which may be quickly and easily installed on a door by any person having average ability and not necessarily a skilled tradesman.

It is yet another object of this invention to provide a latch guard which may be securely held in position by the existing lock if surface mounted, or may be readily driven into the side edge of a wooden door if the lock is mortised therein.

It is still another object of this invention to provide a latch guard in modified form to facilitate packaging and which may be quickly and easily assembled for use.

These and other objects and features of this invention will become apparent when taken in conjunction with the accompanying drawings in which:

FIG. 1 is a perspective view of a latch guard embodying the present invention.

FIG. 2 is a fractional perspective view of a door and lock, having the latch guard, as illustrated in FIG. 1, installed thereon.

FIG. 3 is a fractional, front elevation of the door and lock with latch guard installed, as shown in FIG. 2, showing the method in which said latch guard blocks off access by partly surrounding the otherwise exposed portion of the sliding latch when the door is locked.

FIG. 4 is a perspective view of a modification of the invention permitting it to be packaged more easily.

Referring to FIG. 1, a latch guard comprises a thin but rigid plate 11 of sheet metal or the like of substantially elongated rectangular configuration. Two oppositely lo cated end portions 12 and 13 of plate 11 are bent at right angles thereto to form side wings and the material at the corners so formed 14 and 15 respectively, are partly cut away to form two slits 16 and 17 respectively.

Thus a longitudinal edge 18 of the remaining body portion 19 of plate 11, a longitudinal edge 20 of side wing 12 and a similar edge 21 of side wing 13 are coplanar and form three sides of a rectangle, and will for the purpose of this description be described as the outer edges of their respective structures.

"ice

The inner, longitudinal edge 22 or" body portion 19 is heavily indented to form a plurality of serrations 23 and the free, inner longitudinal edges 24 and 25 of wings 12 and 13 respectively are formed arcuately outwardly of plate 11 to cause wings 12 and 13 to have a flared configuration and it will be noted that serrated edge 22 of body portion 19 extends inwardly for a greater distance than wings 12 .and 13.

A plurality of sharp projecting points 23w are stamped out of body 19 in the vicinity of serrations 23, pointing towards edge 18 thereof.

It will also be noted that a plurality of V notches 26 are formed in widely spaced apart relationship along the inner edges 24 and 25 and outer edges 20 and 21 of wings 12 and 13 respectively to permit the material at these locations to be easily clipped oil by means of shears or even by bend reversal, utilizing pliers or the like, so that wings 12 and 13 may be adjusted to the depth of any average lock during the fitting of latch guard 10 thereto, as hereinafter described.

Referring to FIGS. 2 and 3, latch guard 10 as shown in FIG. 1 is illustrated installed on a door 27 in combination with the bolt mechanism of a spring-latch lock 28.

Upon installation, in this particular surface type installation, the screws 29 retaining lock 28 on the rear surface 30 of door 27 are loosened and the serrated edge 22 of body 19 inserted between lock 28 and rear surface 30 of door 27 until the inner edges 24 and 25 of wings 12 and 13 respectively contact face 31 of lock 28. The outermost portion 32 of body 19, therefore, also extends outwardly from face 31 of lock 28, the amount of extension being equal to the gap 33 existing between lock face 31 and striker plate 28a on the contiguous jamb 34. With screws 29 still loosened the door is closed slowly while the outer edges 18, 20 and 21 of guard 11 can be guided into position to contact striker plate 28a while the spring tension of the arcuate wings keep the inner edges 24 and 25 of wings 12 and 13 in tight contact with face 31 of lock 28, thus the correct positioning of plate 11 is automatically controlled. The tightening of lock screws 29 now will hold guard 10 permanently in this correct position and points 23a are caused to engage in the wood of door 27 in a ratchet like action, thus preventing guard 10 from moving outwardly of lock 28 after final installation.

In this manner, wings 12 and 13 extend. inwardly from adjacent the outer edge of the slide bolt 35 of lock 28 and flank the upper and lower sides thereof, while extending portion 32 of body 19 is in close relation with the bevelled face of bolt 35, and the rectangle thus formed completely and exactly fills the gap 33.

As previously described, wings 12 and 13 may be quickly and easily reduced in length, utilizing notches 26, so that they will not extend beyond the limit of lock 28.

Thus, upon door 27 being closed and locked, as shown in FIG. 3, latch guard 10, although not interfering in any way with the normal action of bolt 35 of lock 28, when the key is used, will prevent the manipulation thereof by even the thinnest strip of sheet metal, plastic or the like which may otherwise be inserted into gap 33. In this manner, many minor burglaries utilizing this method of breaking and entering may be successfully foiled.

In the event that lock 28 is mortised into door 27, serrations 23 materially assist in enabling body 19 of latch guard -10 to be driven into the wood of the edge 31 of door 27 to achieve the same effect as that previously described.

Referring to FIG. 4, a latch guard 40 is shown which is adapted to have an identical method of installation and operation to latch guard 10, guard 40 however is adapted to facilitate packaging and is therefore divided into a separate body portion 41 and wing portion 42.

The longitudinal outer edge 43 of body 41 is folded over to form a channel piece 44 and the opposite longitudinal edge 43a is heavily serrated in the same manner as edge 22 of guard A plunality of points 41a also extend'outwardly from body portion 41 to assist the locking action of body 41 when installednpon asdoor in a manner similar to that of points 2311 of guard 10.

Wing portion 42 is dividedinto a centre piece 45 having two wings 46 and 47 extending outwardlytherefromet substantially right angles. Two slits 48 and 49-are located at the'corners :formed between centre piece; 45 and. Wings 46 and 47' respectively to permit the latter to be flaredarcuately outwardly in' a similar configuration to wings 12 and 13 of guard 10 :as illustrated in FIG. 1'.

A plurality of oppositely located pairs of spaced apart notches 26a are also formed in wings 46 and 47 for length adjustment in a manner similar to that described for latch guard 10.

"As shown in dotteddetail, centre piece 45 of wing portion 42 may be inserted in channel 44 of body 41, the combination of wing assembly 42 and body 41, being a fullmechanical equivalent of latch guard 10;

The general design of the individual parts of the invention as explained above may be varied according to the requirements in regards to manufacture and production thereof, while still remaining within the. spirit and principle of the invention, Without prejudicing the novelty thereof.

The embodiments of this invention in which an exclusive property or privilege is claimed are defined asfollows: 1'. A latch guard blocking ofi. access to the slide bolt in a spring latch lock; said latch guard including a flat, rectangular, rigid body member; two elongated rectangular wing members extending angularly outwardly from opposite short edges of said body member, forming corners her in the direction of said outer longitudinal edge.

2. A latch guard as defined in claim 1, said edges of said wing members being notched; said notches being spaced apart to .'facilitate selective removal of end portions of said Wing members toadjustthe length thereof.

3. A latch guard including a body member of substantially rectangular oonfigurat ionhaving a plain longitudinal edge and a serrated longitudinal edge; said plain edge being bent inwardly to form a channel; a strip retainable in said channel, extending outwardly thereof at each end to form Wing portions; said wing portions being bent substantially at right angles to said body portion; slits at the bends thereof; each of said wing portions being of elongated rectangular configuration having a free longitudinal edge and a fixed longitudinal edge; saidwfree edges being flared outwardly and both said free edges and said fixed edges notched at intervals to facilitate the clipping thereof to a selected length.

Goodwin Nov. 18, 193-0 Garberding Oct. 11', 1949 

3. A LATCH GUARD INCLUDING A BODY MEMBER OF SUBSTANTIALLY RECTANGULAR CONFIGURATION HAVING A PLAIN LONGITUDINAL EDGE AND A SERRATED LONGITUDINAL EDGE; SAID PLAIN EDGE BEING BENT INWARDLY TO FORM A CHANNEL; A STRIP RETAINABLE IN SAID CHANNEL, EXTENDING OUTWARDLY THEREOF AT EACH OF END TO FORM WING PORTIONS; SAID WING PORTIONS BEING BENT SUBSTANTIALLY AT RIGHT ANGLES TO SAID BODY PORTIONS; SLITS AT THE BENDS THEREOF; EACH OF SAID WING PORTIONS BEING OF ELONGATED RECTANGULAR CONFIGURATION HAVING A FREE LONGITUDINAL EDGE AND FIXED LONGITUDINAL EDGE; SAID FREE EDGES BEING FLARED OUTWARDLY AND BOTH SAID FREE EDGES AND SAID FIXED EDGES NOTCHED AT INTERVALS TO FACILITATE THE CLIPPING THEREOF TO A SELECTED LENGTH. 